I'm using a Mezzo d9 and have done for best part of a year in London, with no time off for rain. Nippy, stiff ride (as no hinge), looks sharp and fits the bill perfectly for multimode commuting. I take mine (plus two kids, one carried - the bike in other hand) on the (frankly crazily busy) north London line to nursery at 8am every morning and then do a 3-4 mile bike into work in town. Every couple of weeks, it goes with me on the train to Cambridge and back when I visit one of my outer offices. And its accompanied me on the tube and bus with no problems at all. No probs in rain, and Mezzo do a nice bag which fits on the back, holds a laptop and a change of clothes, and has a waterproof cover for when it rains and is perfectly presentable as a work bag/case during the day (albeit a slightly pricey one at £65). The fold is great, fast, secure and compact - a bit bigger than the Brompton, about the same size as the Birdy), riding, it feels much more positive and responsive than either the Brompton or the Birdy (a friend with the latter is intending to switch bikes having tried the Mezzo). Its tough as old boots. And at weekends, I use it for trips around far more than my Downtube because its just..fun to ride. i'm an enthusiast - I reckon you ought to borrow one for a test ride and see what you think.